﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace LPR
{
    public class CRC
    {

        #region  CRC16

        private static byte[] aucCRCHi =  {
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
            0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
            0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
            0x00, 0xC1, 0x81, 0x40
        };

        private static byte[] aucCRCLo = new byte[] {
            0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7,
            0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E,
            0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9,
            0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC,
            0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
            0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32,
            0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D,
            0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38,
            0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF,
            0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
            0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1,
            0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4,
            0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB,
            0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA,
            0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
            0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0,
            0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97,
            0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E,
            0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89,
            0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
            0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83,
            0x41, 0x81, 0x80, 0x40
        };

        //通过逆序CRC16表, 逆序CRC计算
        public static byte[] Run(byte[] Frame, int Start, int End)     // 传入要校验的数组名及其长度  
        {
            byte CRCHi = 0xFF;
            byte CRCLo = 0xFF;
            int iIndex = 0;
            for (int i = Start; i < End; i++)
            {
                iIndex = CRCLo ^ Frame[i];
                CRCLo = (byte)(CRCHi ^ aucCRCHi[iIndex]);
                CRCHi = aucCRCLo[iIndex];
            }
            byte[] result = { CRCHi, CRCLo };
            //return (int)(CRCHi << 8 | CRCLo);// CRC校验返回值   // CRCHI 向左移动，就是逆序计算的代表
            return result;
        }

        public static byte[] CRC16(byte[] data)
        {
            int len = data.Length;
            if (len > 0)
            {
                ushort crc = 0xFFFF;

                for (int i = 0; i < len; i++)
                {
                    crc = (ushort)(crc ^ (data[i]));
                    for (int j = 0; j < 8; j++)
                    {
                        crc = (crc & 1) != 0 ? (ushort)((crc >> 1) ^ 0xA001) : (ushort)(crc >> 1);
                    }
                }
                byte hi = (byte)((crc & 0xFF00) >> 8);  //高位置
                byte lo = (byte)(crc & 0x00FF);         //低位置

                return new byte[] { hi, lo };
            }
            return new byte[] { 0, 0 };
        }
        #endregion

        #region  ToCRC16
        public static string ToCRC16(string content)
        {
            return ToCRC16(content, Encoding.UTF8);
        }

        public static string ToCRC16(string content, bool isReverse)
        {
            return ToCRC16(content, Encoding.UTF8, isReverse);
        }

        public static string ToCRC16(string content, Encoding encoding)
        {
            return ByteToString(CRC16(encoding.GetBytes(content)), true);
        }

        public static string ToCRC16(string content, Encoding encoding, bool isReverse)
        {
            return ByteToString(CRC16(encoding.GetBytes(content)), isReverse);
        }

        public static string ToCRC16(byte[] data)
        {
            return ByteToString(CRC16(data), true);
        }

        public static string ToCRC16(byte[] data, bool isReverse)
        {
            return ByteToString(CRC16(data), isReverse);
        }
        #endregion

        #region  ToModbusCRC16
        public static string ToModbusCRC16(string s)
        {
            return ToModbusCRC16(s, true);
        }

        public static string ToModbusCRC16(string s, bool isReverse)
        {
            return ByteToString(CRC16(StringToHexByte(s)), isReverse);
        }

        public static string ToModbusCRC16(byte[] data)
        {
            return ToModbusCRC16(data, true);
        }

        public static string ToModbusCRC16(byte[] data, bool isReverse)
        {
            return ByteToString(CRC16(data), isReverse);
        }
        #endregion

        #region  ByteToString
        public static string ByteToString(byte[] arr, bool isReverse)
        {
            try
            {
                byte hi = arr[0], lo = arr[1];
                return Convert.ToString(isReverse ? hi + lo * 0x100 : hi * 0x100 + lo, 16).ToUpper().PadLeft(4, '0');
            }
            catch (Exception ex) { throw (ex); }
        }

        public static string ByteToString(byte[] arr)
        {
            try
            {
                return ByteToString(arr, true);
            }
            catch (Exception ex) { throw (ex); }
        }
        #endregion

        #region  StringToHexString
        public static string StringToHexString(string str)
        {
            StringBuilder s = new StringBuilder();
            foreach (short c in str.ToCharArray())
            {
                s.Append(c.ToString("X4"));
            }
            return s.ToString();
        }
        #endregion

        #region  StringToHexByte
        private static string ConvertChinese(string str)
        {
            StringBuilder s = new StringBuilder();
            foreach (short c in str.ToCharArray())
            {
                if (c <= 0 || c >= 127)
                {
                    s.Append(c.ToString("X4"));
                }
                else
                {
                    s.Append((char)c);
                }
            }
            return s.ToString();
        }

        private static string FilterChinese(string str)
        {
            StringBuilder s = new StringBuilder();
            foreach (short c in str.ToCharArray())
            {
                if (c > 0 && c < 127)
                {
                    s.Append((char)c);
                }
            }
            return s.ToString();
        }

        /// <summary>
        /// 字符串转16进制字符数组
        /// </summary>
        /// <param name="hex"></param>
        /// <returns></returns>
        public static byte[] StringToHexByte(string str)
        {
            return StringToHexByte(str, false);
        }

        /// <summary>
        /// 字符串转16进制字符数组
        /// </summary>
        /// <param name="str"></param>
        /// <param name="isFilterChinese">是否过滤掉中文字符</param>
        /// <returns></returns>
        public static byte[] StringToHexByte(string str, bool isFilterChinese)
        {
            string hex = isFilterChinese ? FilterChinese(str) : ConvertChinese(str);

            //清除所有空格
            hex = hex.Replace(" ", "");
            //若字符个数为奇数，补一个0
            hex += hex.Length % 2 != 0 ? "0" : "";

            byte[] result = new byte[hex.Length / 2];
            for (int i = 0, c = result.Length; i < c; i++)
            {
                result[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);
            }
            return result;
        }
        #endregion

    }
}
